ISLE: Enable the overlap checker (#5011)

This PR turns the overlap checker on by default, requiring the use of priorities to resolve overlap between rules.

cranelift/isle/isle/isle_examples/link/iflets.isle

@@ -11,7 +11,7 @@
 (decl pure predicate () u32)
 (rule (predicate) 1)
 
-(rule (C a b c (B d e))
+(rule 2 (C a b c (B d e))
       (if-let (B f g) d)
       (if-let h (A a b))
       (A h a))
@@ -20,10 +20,10 @@
       (if (predicate))
       42)
 
-(rule (C a b a b)
+(rule 1 (C a b a b)
       (if-let x (D a b))
       x)
 
 (decl pure D (u32 u32) u32)
 (rule (D x 0) x)
-(rule (D 0 x) x)
+(rule 1 (D 0 x) x)

cranelift/isle/isle/isle_examples/link/multi_extractor.isle

@@ -7,7 +7,7 @@
 
 (decl Rule (u32) u32)
 
-(rule (Rule (E1 a idx))
+(rule 1 (Rule (E1 a idx))
       (if-let (A.B) a)
       idx)
 (rule (Rule _)

cranelift/isle/isle/isle_examples/pass/test3.isle

@@ -56,7 +56,7 @@
 (rule
   (Lower (Iadd ra rb))
   (MachInst.Add (UseInput ra) (UseInput rb)))
-(rule
+(rule 1
   (Lower (Iadd (Producer (Iadd ra rb)) rc))
   (MachInst.Add3 (UseInput ra) (UseInput rb) (UseInput rc)))
 (rule

cranelift/isle/isle/isle_examples/pass/tutorial.isle

@@ -51,12 +51,12 @@
 (extern constructor put_in_reg put_in_reg)
 
 ;; Simple rule for lowering adds.
-(rule (lower (HighLevelInst.Add a b))
+(rule -1 (lower (HighLevelInst.Add a b))
       (LowLevelInst.Add
         (AddrMode.RegReg (put_in_reg a) (put_in_reg b))))
 
 ;; Simple rule for lowering loads.
-(rule (lower (HighLevelInst.Load addr))
+(rule -1 (lower (HighLevelInst.Load addr))
       (LowLevelInst.Load 0 (put_in_reg addr)))
 
 ;; Declare an external extractor for extracting the instruction that defined a
@@ -72,7 +72,7 @@
                          0)))
 
 ;; Rule to sink a load of a base address with a static offset into a single add.
-(rule (lower (HighLevelInst.Add
+(rule 1 (lower (HighLevelInst.Add
                a
                (inst_result (HighLevelInst.Load
                               (inst_result (HighLevelInst.Add

cranelift/isle/isle/isle_examples/run/extractor_ordering_bug.isle

@@ -1,19 +0,0 @@
-
-(type u32 (primitive u32))
-
-(decl identity (u32) u32)
-(extern extractor infallible identity identity)
-
-(decl is_zero (u32) u32)
-(extern extractor is_zero is_zero)
-
-(decl test (u32) u32)
-
-;; This exposes a bug where infallible extractors were running before fallible
-;; ones, as the derived ordering for the `Extract` type was ordering them ahead
-;; of the fallible ones. The result is that the fallible `is_zero` extractor
-;; never runs, as the `identity` extractor will always succeed before it's
-;; called.
-(rule (test (identity x)) x)
-
-(rule (test (is_zero x)) 2)

cranelift/isle/isle/isle_examples/run/extractor_ordering_bug_main.rs

@@ -1,23 +0,0 @@
-mod extractor_ordering_bug;
-
-struct Context;
-impl extractor_ordering_bug::Context for Context {
-    fn is_zero(&mut self, val: u32) -> Option<u32> {
-        if val == 0 {
-            Some(val)
-        } else {
-            None
-        }
-    }
-
-    fn identity(&mut self, val: u32) -> u32 {
-        val
-    }
-}
-
-fn main() {
-    let mut ctx = Context;
-
-    assert_eq!(extractor_ordering_bug::constructor_test(&mut ctx, 0), Some(2));
-    assert_eq!(extractor_ordering_bug::constructor_test(&mut ctx, 1), Some(1));
-}